Container scoreline and tear edge protection

ABSTRACT

In the manufacture of easy-opening containers including a scoreline defining a removable portion of a sheet metal wall, scoreline repair prior to opening and protection for the raw tear edge after opening are provided by a plastic, pressure-sensitive tape. The tape covers the scoreline before opening and presents an edge configuration which overlays the raw tear edge after opening. The tape is scored or can be precut or prescored to provide the necessary raw edge protection overlay. Assembly steps cover formation of a unitary rivet held opener and preparation of the tape to provide the scoreline repair and the tear edge protection.

United States Patent William T. Saunders Weirton, W Va. [2i] AppLNo. 842,456

[72] inventor [22] Filed July 17, 1969 [45] Patented Oct. 5, 1971 [73 Assignee National Steel Corporation [54[ CONTAINER SCORELINE AND TEAR EDGE PROTECTION 9 Claims, 6 Drawing Figs.

3,510,022 5/1970 Heller Primary Examiner-George T. Hall Attorney-Shanley and ONeil ABSTRACT: In the manufacture of easy-opening containers including a scoreline defining a removable portion of a sheet metal wall, scoreline repair prior to opening and protection for the raw tear edge after opening are provided by a plastic, pressure-sensitive tape. The tape covers the scoreline before opening and presents an edge configuration which overlays the raw tear edge after opening. The tape is scored or can be precut or prescored to provide the necessary raw edge protection overlay. Assembly steps cover formation of a unitary rivet held opener and preparation of the tape to provide the scoreline repair and the tear edge protection.

PATENTEDUBT 5m 3, 10,462

WILLIAM r. snuuoens ATTORNEYS CONTAINER SCORELINE AND TEAR EDGE PROTECTION This invention is concerned with manufacture of easy-open containers in which a sheet metal surface is scored to define a tear-out portion. In its more specific aspects, the invention is concerned with an easy-open container and methods of manufacture in which scoreline repair and tear edge protection are provided for the tear-out portion of a sheet metal wall.

Easy-opening sheet metal closures, for example end closures for beverage containers, provide an opening so that the beverage can be consumed directly from the container. Such end closures made from aluminum, for example, include ridges or beads along the scorelinesuch as those shown in the U.S. Pat. to I-Iuth No. 3,225,957, to prevent the lip of a consumer from contacting the raw metal edge of the opening. The sharpness of the raw edge obtained when using steel for such end closures has been a drawback in the utilization of steel end closures for direct consumption beverage containers. Another drawback of coated steel has been the damage to the coating caused by scoring. Repair of the coating is ordinarily required in order to supply a rust proof closure. There has been no satisfactory solution for these problems in the past.

The primary objective of the present invention is to simultaneously provide scoreline repair and tear edge protection for metallic container closures in an economic manner suitable for mass production usage. Referring to the accompanying drawings:

FIG. I is a plan view of an end closure during manufacture,

FIG. 2 is a plan view of an end closure embodying the invention prior to affixing a tab opener,

FIG. 3 is a cross-sectional view of a portion of FIG. 2 along the lines 3-3,

FIG. 4 is a cross-sectional view of a portion of FIG. 3 after opening,

FIG. 5 is a plan view of a portion of the present invention, and

FIG. 6 is a plan view of a completed end closure embodying the invention.

End closure 10 of FIG. 1 includes scoreline l2 circumscribing a tear-out portion I4 on the end wall which is to be removed to provide an opening for drinking directly from a container. Protrusion 16 comprises metal for formation of a unitary rivet for purposes to be described later. Scoreline 18 can be used to facilitate initial opening of the container. Scoreline l2 and scoreline 18, in the embodiment shown, are formed in the exterior surface of panel 20 of the end closure 10. The protrusion 16 extends outwardly with respect to the container.

The invention includes the concept of repairing a scoreline in a sheet metal closure for a container and at the same time providing for protection of the raw tear edge of metal presented after opening of the container. To carry out this concept the invention teaches use of a pressure-sensitive tape 22 as shown in FIG. 2. In this embodiment, the pressure-sensitive tape covers the entire tear-out portion 14 of endwall panel 20 so that the scorelines l2 and 18 are repaired and a rustproof end closure is provided. To provide for raw tear edge protection after opening, the pressure-sensitive tape material 22 includes a tape scoreline 26 positioned to leave a tape overlay 28, as shown in FIG. 4, for covering the raw tear edge after removal of tear-out portion 14.

FIG. 3 shows in cross section a portion of panel 20 through scoreline l2. Tape 22 covers the scoreline 12, tear-out portion I4, and a portion of panel 20. An important feature of the invention is preparation of the tape to permit easy opening of the container while providing tape for raw tear edge protection. The tape scoreline 26 for carrying out this purpose is shown in cross section in FIG. 3.

It should be noted that tape scoreline 26 is located inwardly of the scoreline I2. Stated otherwise, the metal scoreline l2 circumscribes the tape scoreline 26. The lateral spacing, in a horizontal plane as shown in FIG. 3, between the center line of the metal score 12 and the centerline of tape score 26 should be between approximately 0.005 inch and about 0.05 inch.

The object is to have sufficient tape edge overlay remaining after opening of the container to cover at least the outer portion of the tear opening likely to be contacted in drinking from the container, as shown in FIG. 4.

For production purposes, the pressure-sensitive tape is provided in elongated continuous form with provisions for indexing to the production line. Referring to FIG. 5, tape 30 includes perforations at lines 32 to permit easy subdivision of the continuous tape into individual pieces 33, 34 and 35 for attachment to individual end closures. Llne 38 indicates the interior edge configurations of the tape which will overlap the raw edge of the sheet metal. Notches 42 and 44, shown on individual tape piece 34 can be provided on each tape piece for registry with production line apparatus.

In accordance with the invention, the tape can be precut or prescored along line 38. If cut out, edge 38 can terminate along line 46 to provide protection for the scoreline 18 if this scoreline to facilitate initial opening is used. Also a cutout aperture 48 can be provided in the tape for aligning with protrusion 16 for registry of the tape during application. The invention also includes prescoring if the tape as a step in the assembly method to be described subsequently.

FIG. 6 shows the completed end closure with tab opener 50 held in position by unitary rivet 52 which has been formed from the sheet metal protrusion 16 by flattening protrusion 16 to overlay a portion of tab opener 50.

During manufacture, the protrusion 16 is formed in the panel 20 of end closure 10 and the scoreline 12 is formed in the external surface of panel 20. Pressure-sensitive tape 22 is then placed over the scoreline as shown in FIG. 2. In accordance with one embodiment the pressure-sensitive tape is then scored along the line 26. The tape can also be precut or prescored as described earlier. A perpendicular projection of scoreline 26 onto the panel 20 falls within the circumscribing scoreline 12. Tab opener 50 is then placed over protrusion 16 and protrusion 16 is formed into rivet 52 for holding the tab opener to the end closure.

By lifting the free end 56 of the tab opener 50 the container is punctured at end 58 of scoreline 12. By then pulling backwardly on the tab opener 50, the tear-out portion 14 is removed from end wall 20. In the process, the tear-out panel 60 of a scored pressure-sensitive tape 22 is removed while the overly portion 28 of the tape 22 remains in position to cover the raw tear edge when drinking from the container.

The tape material can be a polyester or nylon tape for example, Scotch @Brand pressure-sensitive tape. The tape should be heat resistant to a temperature of at least about F. to permit pasteurizing when the container is used for beer. Pressure-sensitive tapes as thin as 0.001 inch are satisfactory for the purposes of the invention. However the invention not to be so limited since the tape thickness can be increased considerably while maintaining pliability. With thin tapes, scoring of the tape should be carried out to leave about one-half of the tape thickness as residue. Thicker tapes can be scored more deeply.

When the closure wall is fabricated from steel, for example tin-plated steel, a suitable end wall gage is 750/bb., which is about 0.0082 inch thickness; a suitable range of end wall thicknesses for pressurized beverage containers is between about 0.007 inch to 0.012 inch. The residue metal at the metal scoreline should be between about 0.002 inch and 0.0035 inch. The tape overlay is of sufficient width to cover the raw edge material and can vary between approximately 0.005 inch to about 0.05 inch.

In addition to providing scoreline repair and tear edge protection, the tape can be used for other purposes such a labeling opening instructions, and the like. Also the area protected by the scored tape is not limited to the metal scoreline and contiguous portions of the closure wall but can be extended in area to cover all or substantially all of the closure wall.

The scope of the present invention should not be limited to the details of specific embodiment structure set forth for purposes of disclosure but rather should be determined from the appended claims.

What is claimed is:

1. An easy-open container assembly comprising a sheet metal closure wall for a container,

a scoreline of reduced metal thickness defining a tear-out section of the closure wall, and

pressure-sensitive tape adhesively secured to the exterior surface of the closure wall about the tear-out section and overlying the metal scoreline along a major portion of its length, the pressure-sensitive tape having a defined inner line contiguous to the metal scoreline, with the metal scoreline circumscribing a perpendicular projection of such defined inner line onto the closure wall so that an inner peripheral edge of the pressure-sensitive tape overlies a major portion of raw metal edge of the closure wall after removal of the tear'out section from the closure wall.

2. The assembly of claim 1 in which the scoreline defining a tear-out section of the closure wall is formed on an exterior surface of the closure wall.

3. The assembly of claim 1 in which the pressure-sensitive tape overlies the entire length of the metal scoreline.

4. The assembly of claim 1 in which the pressure-sensitive tape is heat resistant to a temperature of at least F.

S. The assembly of claim 1 in which the sheet metal is selected from the group consisting of steel and steel coated with a nonferrous metal.

6. The assembly of claim 5 in which sheet metal has a thickness gage between about 0.007 inch and about 0.012 inch and the thickness of the residue metal after scoring is between about 0.002 inch and 0.0035 inch 7. The assembly of claim 1 in which the inner line of the pressure-sensitive tape is defined by a tape scoreline of reduced tape thickness.

8. The assembly of claim 1 in which the inner line of the pressure-sensitive tape is defined by a cutout portion of the tape.

9. The assembly of claim 1 in which the spacing along the closure wall the perpendicular projection between the inner line of the tape and the metal scoreline is at least 0.005 inch.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3. Dated OCTOBER 5, 1971 Inventor s) WILLIAM T SAUNDERS It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

COLUMN 1, line 41, "on" should be --of-.

COLUMN 2, line 22, "if" should be -of---;

line 51, insert --is-- before "not to be";

line 58 "750/bb. should be line 64, insert --of thebefore "material" Signed and sealed this 18th day of April 1972.

(:3 EAL) Attest:

EDWARD ILFLETCILJIH, JR HQBIIHT GOTTSCI IALK Attesting Officer Commissioner of Patents ORM PO-10 0 (IO-69) USCOMM-OC wan-Pun i LLB GOVIINIAIIIT 'IIN'IIIIG O'HCE: "GI 0-!li-LH 

1. An easy-open container assembly comprising a sheet metal closure wall for a container, a scoreline of reduced metal thickness defining a tear-out section of the closure wall, and pressure-sensitive tape adhesively secured to the exterior surface of the closure wall about the tear-out section and overlying the metal scoreline along a major portion of its length, the pressure-sensitive tape having a defined inner line contiguous to the metal scoreline, with the metal scoreline circumscribing a perpendicular projection of such defined inner line onto the closure wall so that an inner peripheral edge of the pressure-sensitive tape overlies a major portion of raw metal edge of the closure wall after removal of the tear-out section from the closure wall.
 2. The assembly of claim 1 in which the scoreline defining a tear-out section of the closure wall is formed on an exterior surface of the closure wall.
 3. The assembly of claim 1 in which the pressure-sensitive tape overlies the entire length of the metal scoreline.
 4. The assembly of claim 1 in which the pressure-sensitive tape is heat resistant to a temperature of at least 150* F.
 5. The assembly of claim 1 in which the sheet metal is selected from the group consisting of steel and steel coated with a nonferrous metal.
 6. The assembly of claim 5 in which sheet metal has a thickness gage between about 0.007 inch and about 0.012 inch and the thickness of the residue metal after scoring is between about 0.002 inch and 0.0035 inch
 7. The assembly of claim 1 in which the inner line of the pressure-sensitive tape is defined by a tape scoreline of reduced tape thickness.
 8. The assembly of claim 1 in which the inner line of the pressure-sensitive tape is defined by a cutout portion of the tape.
 9. The assembly of claim 1 in which the spacing along the closure wall the perpendicular projection between the inner line of the tape and the metal scoreline is at least 0.005 inch. 